A Description of the Global, Monthly, Fossil-Fuel Carbon Dioxide Time Series Based on National Estimates

Increased analysis has led to the realization that a detailed, mechanistic understanding of the global carbon cycle needs more detailed description in multiple dimensions (e.g., finer spatial scales, finer temporal scales, more accurate and precise mass fluxes, isotopic descriptions, ...). Carbon dioxide emissions from fossil fuels are central to the increased interest in the carbon cycle and are critical toward a more detailed understanding of other fluxes in the carbon cycle. This presentation describes recent efforts that have produced a more detailed description of fossil-fuel-derived carbon dioxide emissions at finer spatial and temporal scales. The efforts describe, explicitly, a majority of the total fossil-fuel-derived carbon dioxide emission flux and, via extrapolation, the entire fossil-fuel-derived carbon dioxide emission flux. The extrapolation is based on selecting representative monthly descriptions from among the 21 countries studied in detail to represent the monthly distribution of emissions for the remaining countries of the world. These selections are based on similarities in economy and climate. Emission fluxes will be characterized in both mass and stable carbon isotope space. These results, when combined with global carbon cycle models, should lead to a better understanding of the global carbon cycle. Monte Carlo simulations will be applied to the individual, national, monthly time series to generate possible, future, monthly time series. The domain of inputs to the Monte Carlo simulation will be the actual monthly time series generated for each of the 21 countries examined in detail. For most of these countries, monthly time series that span multiple years were constructed, although some of the data series are quite short. In addition, each of these 21 countries has individual time series for gas, liquid and solid fuels; each of which will be subjected to Monte Carlo analysis. The national results will then be aggregated into a global, monthly time series. The resultant global time series of emissions estimates will cover an extended time period even though the individual, national data sets are of varying length and not necessarily synchronous. The results of the Monte Carlo analysis should be useful to the larger community for representing the historic or estimating the future patterns of fossil-fuel use and their resulting carbon dioxide emissions. Past analyses of the monthly time series for individual countries have shown significant differences in the month-to-month emissions as opposed to a 1/12 distribution (a typical default distribution pattern obtained by dividing annual emissions equally among the 12 months). The global monthly time series shows statistically significant differences from the 1/12 distribution. Past analyses of the stable carbon isotope signature (del 13C) of the monthly time series for individual countries have shown significant changes in the month to month signatures. This is due to the distinct isotopic signatures of solid, liquid and gaseous fuels and the monthly variations in the mass of each fuel consumed. These signatures will now be applied to the global, monthly time series and similar, significant changes are expected to be revealed in the month to month signatures.